I could talk all day about the importance of having a food storage: temporary job loss, natural disaster, flu pandemic, but the point is, it's SMART to have food set aside, but it's also daunting. Hopefully you won't feel quite so overwhelmed after we explore this method of organizing and collecting food storage.
Keep in mind that this is just one way out of many possibilities, and this is an example, not a plan to copy. Although I don't mind if you borrow some of the meal ideas.
First thing to do is see how much food you are going to need. In the case of the 3-month supply, what does 3 months entail?
Breaking down three months (in red) equals 13 weeks of food or 91 dinners, 91 lunches, and 91 breakfasts. (This is an approximation based on 1 month being 31 days and the other 2 months being 30 days, but break it down however you like). (Yes, I added wrong on my paper--but this is just a sample so don't worry about it!)
Now in yellow I have assigned each week to a menu ('A' or 'B'). So, when I say "menu", I'm talking about 7 days of food. I will repeat these menus over and over because I am not willing to stock and plan 91 different dinner meals! My family can live on repeats for three months, especially if the alternative is no food at all. If you feel like you could eat the same thing each week, then plan one week's worth of meals. I don't think I could eat the same thing every week, so I'm planning two weeks of menus that I will rotate. If that still sounds too repetitive for you then plan three weeks of menus, or even four. It's up to you and your family, and what you can store.
So for my menu there will be 7 weeks (49 dinners) on the 'A' menu week and 6 weeks (42 dinners) on the 'B' menu week (dinners only).
Next we need to plan our menus. Use the food guideline recommendations to make sure that the meals are balanced and healthy. Please plan for your own family's needs and likes. This is simply an example. Keep in mind that you may have electricity during this time or you may not. I'm choosing to plan for the worst case scenario and only choose meals around nonperishable items. Chances are you could have electricity...but it's not a risk I'm willing to take, plus these foods will store for longer!
Notice how many times I will be eating these meals (in red). It's important to figure this out so you can estimate how much food you will need to store. Especially for those bulk items that don't come in individual serving sizes.
Then write down what goes into each meal, all the ingredients. Don't forget spices and oil and things like that, there's no need for your food storage meals to be bland.
Now add up what you would need for all the meals. Since I'm having spaghetti 7 times, I will need: 7 jars of spaghetti sauce, 7-1 lb boxes of spaghetti noodles and 14 cans of vegetables (2 cans/night for our family of 4). This is the most difficult part of the process: deciding how much we eat of everything. Keep in mind that it is better to overestimate than to underestimate.
Finally, add everything up (in yellow) and make a master shopping list. List how many jars of spaghetti sauce you need, how many cans of fruit. Once you have this completed, check it with your food storage inventory you already have to see if you can reduce the amount of food on your master list.
Now you have a list of things you need. Obviously you will not go to the store and buy 94 cans of fruit at once, but you can buy little by little. Take advantage of the sales, and keep track of what you buy AND what you eat. It might be helpful to have an excel spreadsheet or a chart to help you keep track of what you are buying/storing and what you are using (we are going to start talking more about how to rotate food in a few weeks).
Please note: this is not a complete list! This will not feed your family for three months! This is just a sample!
I hope this walk-through has helped you become a little more confident about gathering a 3-month supply. It REALLY is doable if you plan and work on it little by little.